Upgrade Rails from latest version 6 to latest version 7

[brotandgames]

Is your feature request related to a problem? Please describe.

Rails 6 is EOL.

• https://rubyonrails.org/maintenance
• https://endoflife.date/rails

Describe the solution you'd like

• Upgrade Rails from latest version 6 to latest version 7
• Adjust Dockerfile (switch from ruby alpine to slim)
• Transition from sprockets to import maps
• Reconcile bootstrap and tabler gem

Describe alternatives you've considered

N/A

Additional context

N/A